Oxidation of hydrocarbons



1940- w. H. KAING El AL 2,215,473

' I OXIDATION OF HYDROOARBONS Original Filed April 2, 193a 4 liquidflya'rocarbqn I Gar confaz'm'zzg free Oxyge 5 -Pre healer ReactionChamber A d elzya'e: and Adai William ilkz'ng Clyde jhgely I INVENTORSwzmkem ATTORNEY Patented Sept. 24, 1940 oxma'rrou or maocaanous WilliamH. King, New Orleans, La., and Clyde Q. Sheely, State College, Miss.

Original application April 2, 1938, Serial No. 199,636. Divided and thisapplication July 26.

1939, Serial No. 286,614

1 Claim.

This invention relates to a new and improved process forthe preparationof chemical compounds by the oxidation of aliphatic hydrocarbons in thepresence of a catalyst, and more par- 5 ticularly to such a processwherein the reaction products comprise aliphatic alcohols, aldehydes andacids. This application is a continuation-in-part of ourcopendingapplication Serial No. l08,478,-iiled 1. October 30, 1936, andis a division of our copendilisglaapplication Serial No. 199,636, filedApril 2, The higher aldehydes of the aliphatic series have considerablevalue as chemical compounds 15 and a number of them have found use inindustry as perfumes. The difliculties in the way of preparing suchcompounds, however, have kept their costs so high as to limit theirfield of usefulness. An improved and simpler method of 2 obtaining suchaldehydes would make more accessible a very desirable class of products.The same condition holds in the case of a number of the higher aliphaticalcohols and acids also,

for example, those containing in the neighbor-' 25 hood of 8 to 12carbon atoms.

- An object of our invention is an improved method for the production ofalcohols, aldehydes, and acids-by the incomplete oxidation of allphatichydrocarbons. A furtherobiect is such a process in which carefullycontrolled conditions allow a high degree of efficiency in thepreparation of the desired products. A still further obiect is a processin which the several products obtained may be separated in relativelypure 35 form. Additional objects will be disclosed as the process isfurther described hereinafter.

We have found that the foregoing objects may be accomplished by theprocess of our invention which comprises introducing a normally liquid 4hydrocarbon in the vapor phase into a heated chamber, together with anoxidizing agent comprising a gas containing free oxygen. The oxidationstep is carried out in the presence of copper oleate as a catalyst.Within the reaction 45 chamber the mixed gases and vapors are subjectedto a temperature between 250 and 500 C. While the oxidation of thehydrocarbons constitutes an exothermic reaction, the heat evolved willnot be sufficient to maintain the desired tempasture and extemal heatingwillbe necesmately mixed and where a temperature of 250 to 500 C. ismaintained, said catalyst, promoting condensed in I I.

saw. It is essential that'the reaction period be kept at a relativelyshort time-interval, and we have found 15 seconds to be the maximumallowable time. Preferably we employ a reaction period not greater than12 seconds, in order that 5 the oxidation may not proceed too far. Thereacting materials and reaction products are removed from the heatedchamber while still in the vapor phase and are condensed by any desiredmethod and apparatus under such conditions and m in such anatmospherethat further reaction cannot take place. The amount ofhydrocarbon will be above the explosive limit in all cases. We havefound it desirable to use an'amount of hydrocarbon of at least by volumeof the gaseous reaction mixture, and preferably between and 40%.

It will be a desirable step in our process also to utilize the unreactedhydrocarbon resulting from the process and to recycle it to anadditionalsimilar oxidation step, whereby the ad vantages of the presence of anexcess of hydrocarbon are obtained with no loss in non-reactingmaterial.

The accompanying drawing shows diagrammatically a flowsheet of. onemethod of carrying out our process. From a reservoir I, the normallyliquid hydrocarbon is forced through conduit 2 intothe preheater 3. Thegas con- 'taining free oxygen is passed through conduit 4 through thepreheater 3, enroute to the reaction chamber 5. Both the vaporizedhydrocarbon and the oxygen containing gas "pass into the reactionchamber 5 where they become intipartial oxidation, being present,whereby partial oxidation of the hydrocarbons is. brought about. Thevapors pass out the conduit 6 into separator I, where any tan formed inthe proc- 40 ess is separated out. The mixed vapors and gases then passthrough condenser 8, where the products capable of condensation becomeliqueifled. The liquid condensate flows into reservoir 9, while a secondvessel III receives any further condensed product not caught in chamber9, but

The reservoirs 9 and III contain the liquefied unreacted hydrocarbonthat has passed through the process, and also condensed water and thealcohols, aldehydes and 5c acids resulting from the oxidation process.Such alcohols, aldehydes and acids will commonly be found in thewater-insoluble layer.

Specific operating conditions suitable for om process for the productionof alcohols, aldehydes, and acids are shown in the following example.This is to be considered as merely illustrative, however, and notlimiting in its application.

Example One gram of copper oleate was dissolved in 200 cc. of naphtha.This mixture was vaporized in the usual manner and mixed with air at atemperature of 387 C. The time of reaction was 5.2 seconds and thepercentage of hydrocarbon in the reaction mixture was 18.7. The yieldobtained was approximately 16% aldehydes and 14% acids.

The method of operation according to the present invention producesalcohols, aldehydes and acids. However, it is especially favorable tothe production of alcohols.

The alcohols, aldehydes and acids resulting from the oxidation ofhydrocarbons according to the process of our invention, are products ofconsiderable economic value and of desirable properties, and the processdescribed offers a novel and advantageous method of obtaining suchproducts. Our process is characterized by higher yields and greaterefiiciency than any process in the art. a

The alcohols, aldehydes and acids may be separated from thehydrocarboncondensate and from one another by the use suitable solvents. In thecase of aldehydes, for example, a saturated solution of sodium bisulfltewas ioimd desirable for extraction, the bisulflte subsequently beingmade alkaline and being subjected to steam distillation. The acids weredesirably extracted by means of sodium hydroxide solution. The alcoholsare preferably extracted by means of phosphoric acid.

While our process has been described in detail in the foregoing, it willbe understood that many variations in procedure may be employed withoutdeparting from the scope of our invention. In the example cited, ahydrocarbon fraction of a specific distillation range was used, but itwould be a highly desirable procedure also to start with a singlealiphatic hydrocarbon, for example octane,-or a mixture of octanes.

We wish to be limited, therefore, only by the following patent claim.

We claim:

The process for producing partially oxidized products of normally liquidaliphatic hydrocarbons which comprises introducing said hydrocarbons invapor phase, together with an..oxidizing agent comprising a gascontaining free oxygen, into a reaction chamber at a temperature between250 C. and 500 C., and reacting said materials for a period notexceeding 15 seconds in the presence 01 copper oleate.

WILLIAM H. KING. CLYDE Q. SHEELY.

